Knee osteotomy blade

ABSTRACT

A knee osteotomy blade comprises a flat metal arm tapered symmetrically from a hub at one end to a cutting head at the other. A spline driver fixed to the hub extends in one direction therefrom and serves to oscillate the arm about the axis of the spline driver. The cutting head has an arcuate series of teeth, a half-tooth being provided at each end of said series to facilitate cutting of a blind groove, alternate teeth in the series being set in opposite directions to produce a groove wider than the thickness of the cutting head.

United States Patent Winter Sept. 16, 1975 [54] KNEE OSTEOTOMY BLADE2,702,550 2/1955 Rowe 128/317 3,554,197 1/1971 Dobbie [75] Invent 214fPaul wmte" Santa Barbara 3,678,934 7 1972 Warfield et a1...., 128/317[73] Assignee: American Sterilizer Company, Erie, Primary n h nn g P PAttorney, Agent, or FirmLyon & Lyon F1 (1: 28,1 74 [22] Jan 9 57ABSTRACT [21] Appl' 437l74 A knee osteotomy blade comprises a flat metalarm tapered symmetrically from a hub at one end to a cut- 52 US. Cl128/317; 30/166 R; 83/782; g head at the other- A Spline driver fixed tothe hub 3 335; 33/ 43 extends in one direction therefrom and serves tooscil- 511 im. (:1. A6lB 17/14; 3278 33/02 late the arm about the axisof the Spline driver- The [58] Field of Search 128/317; 30/166 R;83/782, cutting head has an arcuate series of teeth, a half- 3 35 343tooth being provided at each end of said series to facilitate cutting ofa blind groove, alternate teeth in the 5 References Cited series beingset in opposite directions to produce a groove wider than the thicknessof the cutting head.

2 Claims, 4 Drawing Figures KNEE ()STEOTOMY BLADE BACKGROUND OF THEINVENTION This invention relates to power driven surgical tools and isparticularly directed to an osteotomy saw blade for cutting a blindgroove in the human femur for the polycentric type total knee operation.The configuration of the knee blade greatly improves the cutting abilityin a blind groove without binding or stalling.

Cutting of a blind groove, that is, a groove which has full depth up toits end shoulder, is difficult to accomplish during an operation on thefemur because the bone cuttings tend to pack at the end of the groove.The operation takes place under moist conditions and it is difficult toremove the bone cuttings from the end of the groove while the cuttingaction is taking place.

It is an important object of this invention to provide a novel form ofosteotomy knee blade which overcomes this difficulty.

In accordance with this invention, the cutting head of the blade iscarried on an arm which is oscillated in a small arc in a back and forthmotion, cutting teeth are provided on the head in an arcuate series anda halftooth is formed at each end of the series. The outer face of eachhalf-tooth is shaped to prevent packing of bone cuttings at the end ofthe groove. All of the teeth in the series are set" in oppositedirections to produce a groove wider than the thickness of the cuttinghead.

Other and more detailed objects and advantages will appear hereinafter.

In the drawings FIG. 1 is a side elevation showing a knee osteotomyblade embodying this invention and also showing an attachment for arotary power tool, which attachment is used to oscillate the knee blade.

FIG. 2 is an enlargement'taken substantially on the Line 22 as shown inFIG. 1.

FIG. 3 is an enlargement of the cutting head and arcuate series ofteeth, showing the half-tooth at each end of the series and also showingthat alternate teeth in the series are set in opposite directions.

FIG. 4 is a sectional detail taken substantially on the Line 44 as shownon FIG. 3.

Referring to the drawings, the osteotomy knee blade generally designatedcomprises a flat metal arm 11 which is tapered symmetrically from anenlarged hub 12 to a cutting head 13. The cutting head 13 is wider thanthe adjacent portion of the arm 11, and it is provided with an arcuateseries of cutting teeth 14. The pointed ends of the teeth lie in an arehaving a radius R struck from the axis of the splined driver 18. As

shown in FIGS. 3 and 4, alternate teeth in the series are set" inopposite directions to produce a groove wider than the thickness of thecutting head 13. A half-tooth 15 is formed at each end of the series.The outer surfaces 16 of the half-tooth l5 define an acute angle abetween them.

A driver 18 having external splines 19 is fixed to the arm 11 centrallyof the hub 12 and projects from one side thereof. This spline driver 18is adapted to be received within a splined socket provided in one end 20of an oscillator tool 21. A rotary nut 22 on the other end of theoscillator tool operates a collet chuck to receive one end of astationary part of a rotary power tool, not shown. A mechanism withinthe device 21, not shown, converts the rotary movement of the power toolto oscillatory turning movement of the output socket 23. The arm 11oscillates in a plane about the axis of the spline driver 18 and itmoves a few degrees of are sufficient to cause several teeth 14 tooscillate past the same spot in the groove being cut.

Bone cuttings do not pack at the blind ends of the groove because theteeth 15 at the ends of the series of teeth are only half-tooth inwidth. Moreover, the end surfaces 16 are undercut as shown by the anglea.

Having fully described my invention, it is to be understood that I amnot to be limited to the details herein set forth but that my inventionis of the full scope of the appended claims.

I claim:

1. A blade of the type described, comprising a metal arm extending froma hub at one end to a cutting head at the other end, a driver fixed tothe hub for oscillating the arm in a plane about the axis of the driver,the cutting head having an arcuate series of teeth, to cut a groove, ahalf-tooth being provided at each end of said series, the outer surfaceof each half-tooth being undercut to prevent packing of cuttings atblind ends of the groove being cut.

2. A blade of the type described, comprising a fiat metal arm taperingfrom a hub at one end to a cutting head at the other end, a splinedriver fixed to the hub for oscillating the arm in a plane about theaxis of the spline driver, the cutting head having an arcuate series ofteeth, alternate teeth in the series being set in opposite directions toproduce a groove wider than the thickness of the cutting head, ahalf-tooth being provided at each end of said series, the outer surfaceof each half-tooth being undercut to prevent packing of cuttings atblind ends of the groove being cut.

1. A blade of the type described, comprising a metal arm extending froma hub at one end to a cutting head at the other end, a driver fixed tothe hub for oscillating the arm in a plane about the axis of the driver,the cutting head having an arcuate series of teeth, to cut a groove, ahalf-tooth being provided at each end of said series, the outer surfaceof each half-tooth being undercut to prevent packing of cuttings atblind ends of the groove being cut.
 2. A blade of the type described,comprising a flat metal arm tapering from a hub at one end to a cuttinghead at the other end, a spline driver fixed to the hub for oscillatingthe arm in a plane about the axis of the spline driver, the cutting headhaving an arcuate series of teeth, alternate teeth in the series beingset in opposite directions to produce a groove wider than the thicknessof the cutting head, a half-tooth being provided at each end of saidseries, the outer surface of each half-tooth being undercut to preventpacking of cuttings at blind ends of the groove being cut.